title: Hepatic stearoyl-CoA desaturase (SCD)-1 activity and diacylglycerol but not ceramide concentrations are increased in the nonalcoholic human fatty liver.
abstract: OBJECTIVE
  To determine whether 1) hepatic ceramide and diacylglycerol concentrations, 2) SCD1 activity, and 3) hepatic lipogenic index are increased in the human nonalcoholic fatty liver.
  
  
  METHODS
  We studied 16 subjects with (n = 8) and without (n = 8) histologically determined nonalcoholic fatty liver (NAFL(+) and NAFL(-)) matched for age, sex, and BMI. Hepatic concentrations of lipids and fatty acids were quantitated using ultra-performance liquid chromatography coupled to mass spectrometry and gas chromatography.
  
  
  RESULTS
  The absolute (nmol/mg) hepatic concentrations of diacylglycerols but not ceramides were increased in the NAFL(+) group compared with the NAFL(-) group. The livers of the NAFL(+) group contained proportionally less long-chain polyunsaturated fatty acids as compared with the NAFL(-) group. Liver fat percent was positively related to hepatic stearoyl-CoA desaturase 1 (SCD1) activity index (r = 0.70, P = 0.003) and the hepatic lipogenic index (r = 0.54, P = 0.030). Hepatic SCD1 activity index was positively related to the concentrations of diacylglycerols (r = 0.71, P = 0.002) but not ceramides (r = 0.07, NS).
  
  
  CONCLUSIONS
  We conclude that diacylglycerols but not ceramides are increased in NAFL. The human fatty liver is also characterized by depletion of long polyunsaturated fatty acids in the liver and increases in hepatic SCD1 and lipogenic activities.
authors.affiliation: Department of Medicine, Division of Diabetes, Helsinki, Finland. anna.kotronen@helsinki.fi
authors.forename: Anna
authors.initials: A
authors.lastname: Kotronen
authors.forename: Tuulikki
authors.initials: T
authors.lastname: Seppänen-Laakso
authors.forename: Jukka
authors.initials: J
authors.lastname: Westerbacka
authors.forename: Tuula
authors.initials: T
authors.lastname: Kiviluoto
authors.forename: Johanna
authors.initials: J
authors.lastname: Arola
authors.forename: Anna-Liisa
authors.initials: AL
authors.lastname: Ruskeepää
authors.forename: Matej
authors.initials: M
authors.lastname: Oresic
authors.forename: Hannele
authors.initials: H
authors.lastname: Yki-Järvinen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002518:Ceramides / Q000378:metabolism*; D002853:Chromatography, Liquid; D004075:Diglycerides / Q000378:metabolism*; D005234:Fatty Liver / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D008875:Middle Aged; D013230:Stearoyl-CoA Desaturase / Q000378:metabolism*; D055815:Young Adult
chemical_list: D002518:Ceramides; D004075:Diglycerides; D013230:Stearoyl-CoA Desaturase